Can't increase and show score after collecting coins/killing enemies

Questions & Answers
1

I’ve watched several tutorials, read trough several other similar questions, and my score still doesn’t increase, neither did i manage to show it on screen. I’ve spent hours trying to implement this very simple feature and i’m just stuck on it.
The only part i got woking is destroying coins after they’re collected, but nothing more.

Currently, i’m using these scripts for player and score:

Player:

public class Player : MonoBehaviour
{
    public float speed;
    public Rigidbody2D rb;
    Vector2 movement;

    public int coins;
    public AudioSource collectSound;
    public Text score;

    void FixedUpdate()
    {
        movement.x = Input.GetAxisRaw("Horizontal");
        movement.y = Input.GetAxisRaw("Vertical");
        rb.MovePosition(rb.position + movement.normalized * speed * Time.fixedDeltaTime);
    }

    private void OnCollisionEnter2D(Collision2D collision)
    {
        if (collision.gameObject.CompareTag("Coin"))
        {
            collectSound.Play();
            Score.AddScore(1);
            Score.AddCoins(1);
            Destroy(collision.collider.gameObject);
        }
    }
}

Score:

public class Score : MonoBehaviour
{
    public GameObject scoreText;
    public static int score = 0;
    public static int coins = 0;

    void FixedUpdate()
    {
        scoreText.GetComponent<Text>().text = "Score: " + score;
    }

    public static void AddScore(int addscore)
    {
        score += addscore;
    }

    public static void AddCoins(int addcoins)
    {
        coins += addcoins;
    }
}

In the meantime, I give up on trying to add the score system, and i’ll implement other features.

2

Managed to get a working score counter after watching a tutorial on how to make a kill counter.
Vid link: How to Cleverly Polish Your Shooter with a Kill Counter - YouTube

Player:

    Score scoreScript;
    private void Start()
    {
        scoreScript = GameObject.Find("SCO").GetComponent<Score>();
    }

    private void OnCollisionEnter2D(Collision2D collision)
    {
        if (collision.gameObject.CompareTag("Coin"))
        {
            scoreScript.AddScore(2);
            Destroy(collision.collider.gameObject);
        }
    }

Enemy:

    Score scoreScript;
    private void Start()
    {
        scoreScript = GameObject.Find("SCO").GetComponent<Score>();
    }

    public void TakeDmg(int dmg)
        {
            health -= dmg;
            if (health <= 0)
        {
            Die();
        }
    }

    void Die()
    {
        scoreScript.AddScore(5);
        Instantiate(deathEffect, transform.position, Quaternion.identity);
        Destroy(gameObject);
    }

Score:

using System.Collections;
using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

public class Score : MonoBehaviour
{
    public TextMeshProUGUI counter;
    int score = 0;

    void FixedUpdate()
    {
        ShowScore();
    }

    public void ShowScore()
    {
        counter.text = score.ToString();
    }

    public void AddScore(int addScore)
    {
        score += addScore;
    }
}